People often confuse speed with velocity. These two terms are different from each other and should not be interchanged. Difference between speed and velocity is a common question in physics exams. Although both these terms indicate movement with respect of time, still there are numerous differences between the two.
NOTE: SI Unit of both speed and velocity is meter per second.
Table of Differences between Speed and Velocity
|Basis of Difference||Speed||Velocity|
|Definition||Speed is the rate at which an object covers a specific distance.||Velocity is the rate at which an object changes its position.|
|Type||Speed of a scalar quantity||Velocity is a vector quantity.|
|Formula||Formula of calculating speed is:
speed = distance / time
|Formula of calculating velocity is:
velocity = dx / t
where dx is displacement and t is time.
|Direction||Speed remains same if a moving object changes direction.||Velocity changes if a moving object changes direction.|
|Magnitude||Speed can not be zero or negative.||Velocity can be negative, positive or zero.|
|Interrelation||Speed or a moving object may or may not be equal to its velocity.||An object may have several velocities while maintaining the same speed.|
|Example||An object may accelerate from zero to its top speed in a given time but its speed is taken as average speed. For example, a car may accelerate from 0 km/hr to 100 km/hr in five seconds. But its average speed will be counted as its speed.||Direction is always associated with velocity. For example, if an aircraft is moving in south-west direction as a speed of 400 km/hr; its velocity will be 400 km /hr, south-west.|
Speed vs Velocity with Image Example
The following image simply demonstrates the difference between speed and velocity:
The following image shows how change in direction changes velocity while speed may remain same.